The invention relates to foam insulated water heaters, and more particularly to apparatus for sealing foam insulated water heaters.
A conventional foam insulated water heater includes a water tank having therein at least one opening. An internally threaded spud is welded or otherwise secured to the outer surface of the tank in alignment with the opening. An outer jacket surrounds the tank and has therein an opening aligned with the spud. A fitting extends through the opening in the outer jacket and is threaded on to the spud. The fitting is in turn adapted to be connected to a pipe or another component that communicates with the interior of the tank via the spud.
As is known in the art, foam is injected into the space between the outer jacket and the tank in order to insulate the tank. During injection of the foam it is desirable to prevent the foam from flowing out of the opening in the outer jacket. U.S. Pat. No. 4,790,290, which is assigned to the assignee hereof, discloses an apparatus for sealing the opening in the jacket. This apparatus is connected to the spud in place of the fitting during the foaming process. The apparatus is removed and replaced by the fitting after foaming is completed.